Fluid pressure transducer with end clearance control



Oct. 21, 1958 ROTH 2,856,860

7 FLUID PRESSURE TRANSDUCER WITH END v CLEARANCE CONTROL Filed Aug. 3, 1955 2 Sheets-Sheet 1 IN VEN TOR.

BY 60 g Wm Filed Aug. 3, 1955 Oct. 21, 1958 I J. M. ROTH 2,356,860

FLUID PRESSURE TRANSDUCER WITH END CLEARANCE CONTROL 2 Sheets-Sheet 2 INVENTOR,

United States Patent FLUID PRESSURE TRANSDUCER WITH END CLEARANCE CONTROL Jay M. Roth, Uhrichsville, Ohio, assignor to Mechanisms ggrnpany, Tuscarawas County, Ohio, a corporation of r0 Application August 3, 1955, Serial No. 526,179

3 Claims. (Cl. 103-135) improved fluid pressure pump or motor characterized by simplicity and durability of manufacture, capabilities of handling large volumes of fluid at high pressures and possessing improved leak-proofness from high pressure to low pressure areas.

Another object of my invention is the provision in a transducer of the type described and including a casing and a rotor, of means for utilizing the high pressure in the transducer to assist in controlling end clearances between the rotor and the casing.

Another object of the invention is to provide a transducer having a rotor and a casing with portions of the clearance between the casing and the rotor being connected to the low pressure side of the transducer so that leakages are minimized.

Another object of my invention is to provide in a transducer of the fluid pressure type bearing means adapted to press and seal between the end of the rotor and the easing, but with such bearing means being adapted to yield to allow the passage of dirt to thereby improve pump or motor dependability.

Another object of the invention is the provision in a slipper type fluid pressure transducer of means for maintaining a fixed clearance between the casing and the rotor,

but which will be effectively sealed by the fluid transmitted.

Another object of the invention is to provide a transducer in which bearing or sealing means are maintained in proper sealing relation between the casing and the ends of the rotor with such means being pressed eccentrically towards the rotor in a manner to substantially counterbalance the portions of high pressure present in the transducer.

The foregoing objects of my invention, and other objects will become apparent as the description proceeds, are achieved by the provision of a fluid pressure transducer including a casing having a bore, a rotor in the bore having transverse peripheral slots, blade members, and particularly slipper members in the slots and adapted to engage the bore of the casing, a shaft carrying the rotor, bearings for the shaft carried in the casing, fluid pressure means for applying end pressure against at least one bearing to hold it in sealing relation against an end wall of the rotor or in close proximity thereto, means for supplying fluid under pressure to said fluid pressure means from the fluid under pressure present in the transducer, and resilient means applying an initial force to the said one bearing to make the pump operative initially. Usually the fluid pressure means are positioned eccentrically of the rotor axis and substantially opposite to the center of pressure within the transducer, and conduit means are provided for connecting the low pressure side of the trans- 2,856,860 Patented Oct. 21, 1958 ducer to other portions of the hearing or bearings to reduce leaking.

For a better understanding of my invention, reference should be had to the accompanying drawings wherein in Fig. 1 is a vertical cross-sectional view through a transducer of the fluid pressure type and incorporating the principles of the invention;

Fig. 2 is a cross-sectional view, taken substantially on line IIII of Fig. 1;

Fig. 3 is a view of the apparatus of Fig. 1, and taken substantially on line III-III thereof;

Fig. 4 is a view similar to Fig. 1 but illustrating a modified form of the invention incorporating a pressure plate between the bearing and the rotor to effect a seal.

Fig. 5 is a view similar to Figs. 1, 4, and 6 but of a further modification of the invention and illustrating a radially balanced transducer construction and Fig. 6 is a cross sectional view of the apparatus of Fig. 5 taken on line VIII-VIII thereof.

Referring to the form of the invention. illustrated in Figs. 1 to 3, the numeral 10 indicates generally a casing having a central portion 12 provided with a cylindrical bore 14, and end plates 16 and 18 secured removably to the central portion 12 by cap screws 20 and 22, some of which have been omitted for purposes of simplification.

Slidably received in the bore 14 of the casing 10 is a liner 24 which is slidably but nonrotatably held in position by means of a pin 26. The liner 24 is relatively short in an axial direction compared to the length of the bore 14. The liner 24 is provided with an eccentric chamber 28, and received in the chamber is a rotor 30 which is positioned concentrically with the bore 14, so that one side of the rotor 30 is substantially tangent to one side i of the chamber 28, but the other side has a considerable clearance with the chamber, all inknown manner in accord with the usual practice in vane-type fluid pressure transducers.

The outer periphery of the rotor 30 is provided with a plurality, for example six, of circumferentially-spaced, radially-extending and transversely-directed slots 32 (Fig. 2) each slot being adapted to receive for radial movement a blade member 34. Preferably the blade members 34 take the form of slippers, or slipper members, illustrated and described in detail in my copending application Ser. No. 524,760 filed July 27, 1955 and entitled, Fluid Pressure Transducer for Converting Rotary Force to Fluid Pressure, or Vice-Versa. Sulfice it to say here that the 7 slots 32, take preferably a truncated triangular or V shape and in cross-section the slippers 34 are of generally similar but somewhat more sharply angled shape, and with each slipper 34 having an outer face 36 formed on an are substantially similar to the arc of the greatest radius of the chamber 28 against which the outer faces of the slippers 34 slidably engage. The slippers 34 are of an axial length substantially equal to the thickness of the rotor 30, but with the slippers 34 and the rotor 30 being made in the embodiment of the invention illustrated, just slightly less thick in an axial direction than the axial thickness of the liner 24, for example, in a pump adapted to handle high octane aviation gasoline, the rotor and slippers are made .0005 inch shorter axially than the liner 24.

The rotor 30 is secured to a shaft 38 positioned concentrically of the bore 14, and with one end of the shaft 38 extending out through a sealing means 40 in the casing end plate 16 so that the rotor 30 can be driven by external prime mover means when the mechanism is used as a pump, and so that a power take-oil? is provided from the rotor When the transducer is utilized as a motor.

A bearing 42 to one side of the rotor30 journals the inner end of the shaft 38, and a bearing 44 on the other side of the rotor 30 journals the end of the shaft 38 extending out to the casing end plate 16. The bearings 42 and 44 areslidably but nonrotatably received in the bore 14 of the casing, being held in this manner by pin 26.

.Means are provided .formoving the bearing 42 axially against'the rotor 30, or towards the rotor into sealing relation therewith,. and these means take the form of providing a ,clearance ofbetween .010 and .015 inch between the'casing endplate 18 and the adjacent side of the bearing 42. ,In this, clearance is positioned a circular ing'. 44, adjacentthe casingcover plate 16 and packing 40.

A ball valve..56 islheld by a light-pressure spring 58 against a valve seat in the conduit 52 to hold an initial pressure in the packing..40, but with the ballvalve 56 yielding againstthe spring-58 when the pressurein the packing builds up due to leaking of fluid into the packing chamber.

The casing 12 also has an outlet port or opening 60,

land the liner 24 is, formed with openings 62 adjacent the inlet port 54,v and openings64-adjacent the outlet port 60 to complete the porting of the transducer.

. .In theoperation of-the transducerdescribed, it will be understood that with the transducer'operating as a pump, the shaft'38 is driven .by any suitable prime mover, .and .in this connection, it might be noted that I have .found that thenew type series electric motorsoperating atspeeds up. to 10,000 R. P. M. work very well in direct drive. association with my transducer to provide a relatively small size apparatus able to transmit large volumes .of-l1qu1d,..such as. aviation, gasoline at pressures up to 1,000 pounds persquare inch. The application drawings.

in Figs. 1 to 3 illustrate;substantially the actual size of the pump designed and built for this particularpumping .operation; Leakage of-the-pump is held to a -minimurn by having the bearing 42 held against the liner 24 by the high pressure liquid flowing through conduit to the outside of the eccentrically positioned sealing ring 46, and

. with the liner 24 being slightly greater in thickness than the rotor- 30, a good working clearance is maintained.

.The same highpressure forces moving bearing 42 against ;liner- 24 move-liner 24 against bearing 44 and against casing end plate 16 to .hold all of the parts in the de- ..sired relationship. But, the clearance provided between the bearing 42 and the casing end plate 18 allows the ,bearing 42 to move towards the end plate 18 against the resilient forceprovided by the O-ring 46 to allow the pump to clear itself of dirt, particularly t th start f 'P ping-;operation.

.The slippers 34 act in the manner. fully described in my 1 above iden-tified copending application to eflect together with the eccentric position of the rotor 30 in the liner 24 the-pumping action desired.

.1 In the operation of the transducer as a motor, fluid tnnder pressure supplied to the outlet drives the rotor 30 .thereverse direction; and the fluid flows out inlet 54 :to thereby. driveshaft 38 which is secured to the apparatusto be driven in any of the known and usual manners.

The form of the invention shown in Fig. 4 is like that illustrated in Fig. 1 except that a pressure plate is positioned between bearing 44 and rotor 30*, and the pressure sealing O-ring 46 is placed between the bearing 44 'and atthe pressure plate 130. Bearing 4?.- abuts end pla'te;18 .*Pin 26? holds the bearings 44 and 42 *"thepressure'plate 130 and the liner 24 against rotation but allows axial sliding movement. Passages 132 and 134 connect the high pressure side of the transducer to the outside of the O-ring 46 and the low pressure-side to the inside of the O-ring, respectively, the O-ring being positioned eccentrically as heretofore described. The pressure plate 130 is thus held in sealing relation towards the liner 24 and towards the rotor 30 which is made about .0005 inch shorter axially than the liner.

From the foregoing, it will be recognized that the various objects of the invention have been achieved by the provision of a relatively simple, inexpensive, and durable transducer capable of operating with high pressures and large volume.

It should be noted that the principles of the invention herein disclosed can readily be incorporated in a rotationally balanced elliptical chamber transducer having two inlets and two outlets and of the type shown and described in my above identified copending application.

More particularly, Figs. 5 and 6 show such a construction in which casing is provided with a circular bore 142 slidably receiving bearing 144, liner 146 and thrust bearing pressure plate 148 held for axial but nonrotary movement in the bore by pin 150. The liner 146 has an elliptical chamber'152 which rotatably receives rotor 154 secured to shaft 156 carried inbearing 144.

The rotor 154 is shown'as provided with transverse slots receiving slippers 158 which engage in sliding arcuate contact, i. e., greater than line contact, with the chamber 152.

, In order to obtain the radially balanced rotor, which reduces bearing and other wear, two outlets 160 for pressure are provided at substantially diametrically opposed points. The outlets 160 are connected by a manifold opening 162 to the casing outlet 164.

Likewise, opposed inlets 166 are connected by manifold 168 to the casing inlet 170.

Thrust bearing pressure plate 148 is resiliently urged axially against liner 146 (which is about .0005 inch thicker axially than rotor 154) by spring 172, and cover plate 174 is formed with a circular boss 176 slidably received in a cup-shaped opening 178 in the pressure plate 148. An O-ring seal 180 is positioned between boss 176 and opening 178, and fluid from the pressure side of the transducer is introduced behind the pressure plate radially outward of seal 180 by leakage from pressure manifold 168 about the periphery of plate 148 to hold the bearing 144, rotor 154 and thrust bearing pressure plate 148 in sealing relation, a passage 182 connecting. the opening 178 to the manifold opening 162 providing leakage from the center portion or bore 178 of the thrust bearing plate within seal 180 to the low pressure side of the transducer.

'While in accord with patent statutes, certain embodiments of the invention have been illustrated and described in detail, it is to be particularly understood that the invention is not to be limited thereto or thereby, but that its scope is defined in the appended claims.

What I claim is:

1. A fluid pressure transducer including a casing having a substantially circular bore, a liner slidably but nonrotatively received in the bore, said liner having a cylindrical chamber extending axially therethrough with at least a portion of its peripheral surface eccentric to said circular bore a rotor positioned in the chamber, said casing having high pressure and low pressure portions conmeeting with said chamber, slippers carried by the rotor and engaging the. inner wall of the chamber in area contact, said rotor being just slightly thinner in an axial direction than the liner, a shaft secured ;to the rotor and positioned concentric with the bore, a hearing at each side of the rotor and each of said bearings having its outer periphery slidably but non-rotatably received in the bore, an end plate for each end of the-casing, at least one of which is removably secured thereto, the shaft extending through one end plate and at least one of said bearings, and substantially circular resilient means secured between one of the end plates and the adjacent bearing, said high pressure and low pressure portions being separated one from the other by said circular resilient means, and a passage connecting said low pressure portion to the space within said resilient means between the end plate and the adjacent bearing.

2. A fluid pressure transducer of the slipper pump type including a casing having a substantially circular cylindrical bore, an axially narrow liner slidably but nonrotatively received in the bore, said liner having an elliptical chamber extending axially therethrough, a rotor positioned in the chamber, said rotor having circumferentially spaced transverse slots truncated triangular cross section with outwardly divergent walls, slippers carried by the rotor and engaging the inner wall of the chamber in arcuate surface contact therewith, said slippers being of truncated triangular cross section, said rotor being just slightly thinner than said liner in an axial direction, a shaft secured to the rotor, a hearing at each side of the rotor having a check engaging an end face of said liner, each of said bearings having its outer pen'phery slidably but non-rotatably received in the bore of said casing, end walls flanking said bore of said casing, at least one of said Walls being removably secured to said casing, said shaft extending through one of said walls, means for applying high fluid pressure from the high pressure side of said transducer against one of said hearings to force it axially toward said rotor to reduce leakage, said last said means comprising an annular resilient sealing ring of smaller diameter than the bore of said casing and dividing a space between one of said bearings and the adjacent end wall into inner and outer spaces, a passage connecting the inner of said spaces to the low pressure side of said transducer, and means connecting the outer space about the periphery of the bearing to the high pressure side of said transducer.

3. A fluid pressure transducer including casing having a cylindrical bore and diametrically opposite high and low pressure ports connecting therewith, a liner slidably but non-rotatably seated in said bore, said liner having one or more eccentrically positioned pumping chambers therein, a rotor positioned concentrically of said bore,

said rotor having circumferentially spaced outwardly divergent notches, slippers carried in the notches of said rotor, said slippers being of generally trapezoidal cross section with an arcuate base having substantially the curvature of the liner at its greatest curvature for seating against the liner and one arcuate face for engagement with a face of the notch, said rotor being slightly thinner in an axial direction than said liner, a shaft at one side of the rotor and concentric with the bore of the casing, a bearing for the shaft and the adjacent side of the rotor, a thrust bearing pressure plate at the opposite side of the rotor, said bearings having their outer peripheries slidably but non-rotatably received in the bore of the casing, inlet and outlet ports through said liner and manifolds formed between said liner and said bore for connecting said chamber to said high and low pressure ports, and means connected with the high pressure manifold for applying axial pressure to said thrust bearing pressure plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,683,143 Peterson Sept. 4, 1928 1,780,109 Berglund Oct. 28, 1930 1,996,875 McCann Apr. 9,1935 2,044,873 Beust llune 23, 1936 2,312,891 Ferris Mar. 2, 1943 2,521,420 Spotz Sept. 5, 1950 2,525,619 Roth et al. Oct. 10, 1950 2,544,987 Gardiner et al. Mar. 13, 1951 2,544,988 Gardiner et al. Mar. 13, 1951 2,641,192 Lindberg June 9, 1953 2,649,737 Hoen et al. Aug. 25, 1953 2,702,509 Garnier Feb. 22, 1955 2,708,884 Deschamps M. May 24, 1955 2,710,581 Rosaen June 14, 1955 2,728,301 Lindberg Dec. 27, 1955 2,768,582 Klessig et a1 Oct. 30, 1956 2,778,317 Cockburn Jan. 22, 1957 FOREIGN PATENTS 736,267 Germany June 10, 1943 

